I. Field of the Invention
The present invention relates generally to chimney and roof flashing. More particularly, the present invention relates to a system of flashing for securely weatherproofing the intersection of an upright wall or a chimney structure and an inclined shingled roof.
II. Description of the Relevant Art
The tendency of water from rain or snow to seep into every available crack or crevice of a shingled roof is a scourge which has afflicted many an unfortunate home or office dweller. This problem is particularly acute at the intersection of an inclined roof slope and an upright wall or chimney structure. Water tends to seep down along the upright wall or chimney structure, bypassing the roof, and finding its way along the rafters and interior ceilings. The damage resulting from such seepage may be severe, and often results in rotted wood or damaged plaster or plasterboard. Repair costs of these elements of a structure are high.
Conventional responses to such seepage previously include the adaptation of aluminum sheet metal, known as "flashing", to the intersected areas. This flashing is fitted to the joints and angles before the shingles are installed. Conventional flashing is L-shaped in cross section. The horizontal part of the flashing is nailed by means of roofing nails to the wood on a roof before the shingles are applied.
The vertical part of the flashing may be attached to the upright wall or chimney structure by a tar-based adhesive. Alternatively, the mortar from mortar joints between selected bricks may be chipped away, and a small horizontal lip atop the vertical part of the flashing may be inserted into the crevice created by the chipping. With the flashing thus in place, the chipped-away mortar is replaced with fresh mortar or a sealant.
While this conventional approach is commonly used, it suffers from well-known disadvantages. Perhaps the most important of these is that in spite of the great effort of the roofer to provide an effective seal, the capillary action of water almost invariably draws the water along the crevice remaining between the edge of the overlaid shingles and the flashing. Here water is not directed away because unlike the shingles which are overlapping, the flashing of the inclined intersection allows the water to seep therealong, eventually finding its way under the shingles and into the wood.
Conventional methods of applying flashing also suffer from the difficulty associated with applying the vertical part to the upright wall or chimney structure. If a sealant is used, the seal formed thereby is almost always imperfect, thus allowing water seepage. If the mortar is chipped away, great damage may result to all of the associated mortar joints. In any event this approach is very tedious and time consuming and ultimately may also allow water seepage. Even where the two above-described methods of fastening the vertical part to the brickwork are employed together, the seepage of water is still not necessarily prevented.
Accordingly, the prior approaches to solving the problem of providing an effective and convenient flashing system have failed to eliminate the inconvenience and seepage conventionally associated therewith.